Dresden 2026 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 81: Correlated Electrons: Other Materials

TT 81.1: Vortrag

Donnerstag, 12. März 2026, 15:00–15:15, HSZ/0101

Built-in Electric-Field-Driven Rashba Spin-Orbit Interactions in AlO_x/Sr_1−xCa_xTiO₃ Interfaces — •Janine Gückelhorn¹, Sergi Plana-Ruiz^2,3, Gyanendra Singh¹, Saul Estandia Rodriguez¹, Roger Guzman¹, Fernando Gallego⁴, Luis M. Vicente-Arche⁴, Joaquim Portillo⁵, Thanos Galanis⁵, Manuel Bibes⁴, Jaume Gázquez¹, and Gervasi Herranz¹ — ¹Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Bellaterra, Spain. — ²Scientific & Technical Resources, Universitat Rovira i Virgili, Tarragona, Spain. — ³LENS-MIND, Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Spain. — ⁴Laboratoire Albert Fert, CNRS, Thales, Université Paris Saclay, France. — ⁵NanoMEGAS SPRL, Brussels, Belgium.

Two-dimensional electron gases (2DEGs) at oxide interfaces exhibit strong Rashba spin-orbit coupling (SOC), arising from broken inversion symmetry and the resulting built-in electric field. However, the microscopic origin of Rashba SOC remains under debate. Density functional theory points to two key mechanisms as origin: polar lattice displacements and electric-field-driven orbital polarization. We show that the Rashba coefficient in AlO_x/Sr_1−xCa_xTiO₃ 2DEGs increases significantly with Ca substitution, which enhances polarizability and induces ferroelectricity. Separating lattice and electrostatic effects reveals that modest structural changes accompany a near-tenfold rise in the built-in field. Our results demonstrate that nonlinear polarizability, not just structural asymmetry, dictates Rashba SOC strength, establishing polarizability as a key control of SOC in oxide 2DEGs.

Keywords: Two-dimensional electron gas; Spin-orbit coupling; Rashba effect; Quantum paraelectric interfaces; Transition metal oxides